Image Processing Min/Max filter

122 views (last 30 days)
Marco Rossi
Marco Rossi on 28 Apr 2016
Commented: Marco Rossi on 1 May 2016
i'm trying to execute a min/max filtering of an image but i'm meeting some problems. The filter consist in calculating the upper and lower envelope. In particularly for the upper envelop (Ue) i substituted for every pixel the max value in a 3X3-pixel neighborhood, and for the lower envelop (Le) the min value. Finally i calculated the filtered image
Im = (Im - Le) ./ (Ue -Le);
but the result is not correct in my opinion. I think the problem is in the the conversion of the format image because i don't well understand the difference between the commands "im2double" and "double".
This is the code
Im = imread('image.bmp');
Im = im2double(Im);
[r c] = size(Im);
ImL = zeros(r,c);
ImU = zeros(r,c);
for i=2:r-1
for j=2:c-1
M = Im(i-1:i+1,j-1:j+1);
Min = min(M(:));
Max = max(M(:));
ImL(i,j) = Min;
ImU(i,j) = Max;
AirF = (Air-AirL)./(AirU-AirL);
AirF = im2uint8(AirF);
Thanks for help

Answers (1)

Alex Taylor
Alex Taylor on 28 Apr 2016
If you have the image processing toolbox, imerode and imdilate are the min/max filters you are looking for and are much faster than rolling these yourself.
  1 Comment
Marco Rossi
Marco Rossi on 1 May 2016
Thanks for the answer; i didn't know the commands you mentioned, but i'd prefer to implement by myself

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by